The latest report published by the Tufts Center for the Study of Drug Development (CSDD), found that while the number of new cancer drugs entering clinical development had more than doubled since the early 1990s, US marketing approval rates had dropped from 20 per cent for the period 1993-1997 to only 8 per cent during the mid-2000s. While overall success rates had dropped to 8 per cent for all candidates, small molecule drugs achieved a 10 per cent approval rate, while monoclonal antibodies (mAbs) of all types achieved a 9 per cent approval rate. However, humanised mAbs achieved a 14 per cent approval rate the highest of all the classes looked at. The study assessed over 1000 cancer therapeutic of vaccine candidates and included only candidates that had note been previously approved for any indication. In addition the study found that if mAbs were to fail, they failed earlier in their development cycle with mAbs suffering the lowest Phase 1-to-2 and Phase 2-to-3 transitions. However, mAbs had the highest Phase 3-to-FDA review and review-to-approval rates of all drug classes. The centre also reiterated its opinion that R&D efficiency must increase if companies want to stay viable. "While commercial development of cancer treatments has dramatically increased in the last dozen years or so, drug developers are still challenged to boost success rates in this area," said Tufts CSDD director Kenneth Kaitin. "In today's market, increased R&D efficiency is synonymous with long-term commercial viability, and improving success rates is key to enhanced R&D performance."